Preparação de fases estacionarias SiO2(PMOS), imobilizadas por microondas para cromatografia liquida de alta eficiencia

AUTOR(ES)
DATA DE PUBLICAÇÃO

2001

RESUMO

In the preparation of stationary phases (SP), an alternative to minimize the undesirable effects of the silanol groups consists of promoting a better covering of the surface of the silica by the sorption of a polymer onto the support, a sorbed phase being obtained. The stability of these SP is increased by the immobilization process using, as an example, microwave radiation. The main consequence of the phenomena of ionic migration and dipolar rotation, caused by the microwave radiation, is a fast heating of samples composed of ions or polar molecules. The main objective of this work is to use microwave radiation as an alternative method of immobilization, seeking to obtain SP immobilized with high efficiency and stability .Thus SP was prepared by evaporation at room temperature of a misture of poly(methyloctylsiloxane) (PMOS), 10 mm Davisil silica and dichloromethane, and later immobilized in a microwave oven .Values of 22300 plates m were obtained, with an asymmetry factor of 1.5, for sorbed phases, while, for phases immobilized by microwaves at 495 watts for 900 seconds, columns were obtained with 44700 plates m and an asymmetry factor of 1.1. The same preparation procedure was used for PMOS with 5 mm Spherisorb silica, with an efficiency of 89400 plates m and an asymmetry factor of 1.5 being obtained for a phase immobilized by microwaves. The results of elemental analysis for carbon and IR spectroscopy proved the positive effect of the use of microwave radiation for the immobilization of the SP. The SP was applied in the separation of pesticides and in the analysis of diuron and linuron in urine with good separations being obtained, showing the potential of the SP prepared.

ASSUNTO(S)

cromatografia liquida de alta eficiencia microondas ondas estacionarias

ACESSO AO ARTIGO

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